Measurement machine utilizing a barcode to identify an inspection plan for an object

ABSTRACT

Embodiments of the present invention relate to a measurement machine for measuring an object, and more particularly to a measurement machine such as a portable articulated arm coordinate measuring machine or a laser tracker that measures an object according to a measurement or inspection plan that is identified by a machine readable information symbol located on the object to be measured or on a drawing (e.g., a CAD drawing) of the object.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patent application Ser. No. 13/746,741 filed on Jan. 22, 2013, which claims the benefit of U.S. Provisional Application Ser. No. 61/591,290 filed on Jan. 27, 2012, the contents of which are incorporated by reference herein.

BACKGROUND

The present disclosure relates to a measurement machine for measuring an object, and more particularly to a measurement machine such as a portable articulated arm coordinate measuring machine or a laser tracker that measures an object according to a measurement or inspection plan that is identified by a bar code located on the object to be measured or on a drawing (e.g., a CAD drawing) of the object.

Portable articulated arm coordinate measuring machines (AACMMs) have found widespread use in the manufacturing or production of parts or objects where there is a need to rapidly and accurately verify the dimensions of the part during various stages of the manufacturing or production (e.g., machining) of the part. Portable AACMMs represent a vast improvement over known stationary or fixed, cost-intensive and relatively difficult to use measurement installations, particularly in the amount of time it takes to perform dimensional measurements of relatively complex parts. Typically, a user of a portable AACMM simply guides a probe along the surface of the part or object to be measured. The measurement data are then recorded and provided to the user. In some cases, the data are provided to the user in visual form, for example, three-dimensional (3-D) form on a computer screen. In other cases, the data are provided to the user in numeric form, for example when measuring the diameter of a hole, the text “Diameter=1.0034” is displayed on a computer screen.

An example of a prior art portable articulated arm CMM is disclosed in commonly assigned U.S. Pat. No. 5,402,582 ('582), which is incorporated herein by reference in its entirety. The '582 patent discloses a 3-D measuring system comprised of a manually-operated articulated arm CMM having a support base on one end and a measurement probe at the other end. Commonly assigned U.S. Pat. No. 5,611,147 ('147), which is incorporated herein by reference in its entirety, discloses a similar articulated arm CMM. In the '147 patent, the articulated arm CMM includes a number of features including an additional rotational axis at the probe end, thereby providing for an arm with either a two-two-two or a two-two-three axis configuration (the latter case being a seven axis arm).

Another common type of measurement machine for measuring a part or object to determine whether or not that manufactured part or object conforms to the desired design specifications is a laser tracker. A laser tracker measures the 3-D coordinates of a certain point by sending a laser beam to the point, where the laser beam is typically intercepted by a retroreflector target. The laser tracker finds the coordinates of the point by measuring the distance and the two angles to the target. The distance is measured with a distance-measuring device such as an absolute distance meter (ADM) or an interferometer. The angles are measured with an angle-measuring device such as an angular encoder. A gimbaled beam-steering mechanism within the instrument directs the laser beam to the point of interest. The retroreflector may be moved manually by hand, or automatically, over the surface of the object. The laser tracker follows the movement of the retroreflector to measure the coordinates of the object. Exemplary laser trackers are disclosed in U.S. Pat. No. 4,790,651 to Brown et al., incorporated by reference herein; and U.S. Pat. No. 4,714,339 to Lau et al. The total station, which is most often used in surveying applications, may be used to measure the coordinates of diffusely scattering or retroreflective targets. The total station is closely related to the laser tracker.

A common type of retroreflector target is the spherically mounted retroreflector (SMR), which comprises a cube-corner retroreflector embedded within a metal sphere. The cube-corner retroreflector comprises three mutually perpendicular mirrors. The apex of the cube corner, which is the common point of intersection of the three mirrors, is located at the center of the sphere. It is common practice to place the spherical surface of the SMR in contact with an object under test and then move the SMR over the surface of the object being measured. Because of this placement of the cube corner within the sphere, the perpendicular distance from the apex of the cube corner to the surface of the object under test remains constant despite rotation of the SMR. Consequently, the 3-D coordinates of the object's surface can be found by having a tracker follow the 3-D coordinates of an SMR moved over the surface. It is possible to place a glass window on the top of the SMR to prevent dust or dirt from contaminating the glass surfaces. An example of such a glass surface is shown in U.S. Pat. No. 7,388,654 to Raab et al., incorporated by reference herein.

A gimbal mechanism within the laser tracker may be used to direct a laser beam from the tracker to the SMR. Part of the light retroreflected by the SMR enters the laser tracker and passes onto a position detector. The position of the light that hits the position detector is used by a tracker control system to adjust the rotation angles of the mechanical azimuth and zenith axes of the laser tracker to keep the laser beam centered on the SMR. In this way, the tracker is able to follow (track) the SMR as it is moved.

Angular encoders attached to the mechanical azimuth and zenith axes of the tracker may measure the azimuth and zenith angles of the laser beam (with respect to the tracker frame of reference). The one distance measurement and two angle measurements performed by the laser tracker are sufficient to completely specify the three-dimensional location of the SMR.

As mentioned, two types of distance meters may be found in laser trackers: interferometers and absolute distance meters (ADMs). In the laser tracker, an interferometer (if present) may determine the distance from a starting point to a finishing point by counting the number of increments of known length (usually the half-wavelength of the laser light) that pass as a retroreflector target is moved between the two points. If the beam is broken during the measurement, the number of counts cannot be accurately known, causing the distance information to be lost. By comparison, the ADM in a laser tracker determines the absolute distance to a retroreflector target without regard to beam breaks, which also allows switching between targets. Because of this, the ADM is said to be capable of “point-and-shoot” measurement. Initially, absolute distance meters were only able to measure stationary targets and for this reason were always used together with an interferometer. However, some modern absolute distance meters can make rapid measurements, thereby eliminating the need for an interferometer. Such an ADM is described in U.S. Pat. No. 7,352,446 to Bridges et al., incorporated by reference herein. The distances measured by interferometers and absolute distance meters are dependent on the speed of light through air. Since the speed of light varies with air temperature, barometric pressure, and air humidity, it is common practice to measure these quantities with sensors and to correct the speed of light in air to obtain more accurate distance readings. The distances measured by total stations also depend on the speed of light in air.

In its tracking mode, the laser tracker automatically follows movements of the SMR when the SMR is in the capture range of the tracker. If the laser beam is broken, tracking will stop. The beam may be broken by any of several means: (1) an obstruction between the instrument and SMR; (2) rapid movements of the SMR that are too fast for the instrument to follow; or (3) the direction of the SMR being turned beyond the acceptance angle of the SMR. By default, following the beam break, the beam may remain fixed at the point of the beam break, at the last commanded position, or may go to a reference (“home”) position. It may be necessary for an operator to visually search for the tracking beam and place the SMR in the beam in order to lock the instrument onto the SMR and continue tracking.

Some laser trackers include one or more cameras. A camera axis may be coaxial with the measurement beam or offset from the measurement beam by a fixed distance or angle. A camera may be used to provide a wide field of view to locate retroreflectors. A modulated light source placed near the camera optical axis may illuminate retroreflectors, thereby making them easier to identify. In this case, the retroreflectors flash in phase with the illumination, whereas background objects do not. One application for such a camera is to detect multiple retroreflectors in the field of view and measure each retroreflector in an automated sequence. Exemplary systems are described in U.S. Pat. No. 6,166,809 to Pettersen et al., and U.S. Pat. No. 7,800,758 to Bridges et al., incorporated by reference herein.

Some laser trackers have the ability to measure with six degrees of freedom (DOF), which may include three coordinates, such as x, y, and z, and three rotations, such as pitch, roll, and yaw. Several systems based on laser trackers are available or have been proposed for measuring six degrees of freedom. Exemplary systems are described in U.S. Pat. No. 7,800,758 to Bridges et al., U.S. Pat. No. 5,973,788 to Pettersen et al., and U.S. Pat. No. 7,230,689 to Lau.

While existing measurement machines such as portable AACMMs or laser trackers are suitable for their intended purposes, there remains a need for a simplified method of inspecting parts based on machine readable information provided on the parts or on representation of the parts.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the invention, a method for inspecting a part according to an inspection plan is provided. The method uses a portable articulated arm coordinate measuring machine (AACMM) having a base; a manually positionable arm portion having opposed first and second ends, the second end of the arm portion being coupled to the base, the arm portion including a plurality of connected arm segments, each arm segment including at least one position transducer for producing a position signal; a measurement device coupled to the first end of the arm portion; and an electronic circuit which receives the position signal from the at least one position transducer and provides data corresponding to a position of the measurement device. The method includes the steps of generating an inspection plan for a part to be inspected to determine at least one characteristic of the part. A machine readable information symbol is generated that includes information that identifies the generated inspection plan. The generated machine readable information symbol is associated with the part. The machine readable information symbol from the part is read with a reader device configured to translate the machine readable information symbol to determine the information contained therein, the reader device being coupled to communicate with the AACMM. The at least one part characteristic is measured according to the generated inspection plan identified by the machine readable symbol.

According to another embodiment of the invention, another method for inspecting a part according to an inspection plan is provided. The method uses a laser tracker having a light source that emits a light beam towards a target located within an environment, and a reader device that captures the light beam reflected back to the laser scanner from the target located within the environment. The method includes the steps of generating an inspection plan for a part to be inspected to determine at least one characteristic of the part. A machine readable information symbol is generated that identifies the generated inspection plan. The generated machine readable information symbol is associated with the part. The machine readable information symbol is read with the reader device associated with the laser tracker. The part is inspected according to the generated inspection plan identified by machine readable information symbol read by the reader device.

According to another embodiment of the invention, a system for inspecting a part according to an inspection plan is provided. The system includes a measurement machine configured to measure at least one characteristic of the part. A device having a processor is provided. The processor being responsive to executable computer instructions when executed on the processor for generating an inspection plan for a part to be inspected to determine at least one characteristic of the part, the processor further being responsive to generating a machine readable information symbol that includes information that identifies the generated inspection plan in response to the inspection plan being generated. A reader is coupled to communicate with the measurement machine and the device, the reader being configured to translate the machine readable information symbol to determine the information contained therein.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, exemplary embodiments are shown which should not be construed to be limiting regarding the entire scope of the disclosure, and wherein the elements are numbered alike in several FIGURES:

FIGS. 1A and 1B are perspective views of a portable articulated arm coordinate measuring machine (AACMM) having embodiments of various aspects of the present invention therewithin

FIGS. 2A-2D taken together, is a block diagram of electronics utilized as part of the AACMM of FIG. 1A in accordance with an embodiment;

FIGS. 3A and 3B taken together, is a block diagram describing detailed features of the electronic data processing system of FIG. 2A in accordance with an embodiment;

FIG. 4 is a perspective view of the AACMM of FIG. 1 with the display arranged in an open position;

FIG. 5 is a flowchart of various steps in a method according to an embodiment of the present invention for generating an inspection plan for a part to be inspected, for generating a bar code associated with that inspection plan, and for reading the bar code and carrying out the steps in the inspection plan;

FIG. 6 is a view of a display screen illustrating one step in the method of FIG. 5 showing the generation of an inspection plan for a part to be inspected, according to an embodiment of the present invention;

FIG. 7 is a view of a display screen illustrating another step in the method of FIG. 5 showing the assignment of a bar code to the inspection plan generated for the part to be inspected, according to an embodiment of the present invention;

FIG. 8 is a view of a display screen illustrating another step in the method of FIG. 5 showing the bar code assigned to the corresponding inspection plan generated for the part to be inspected, according to an embodiment of the present invention;

FIGS. 9A and 9B show the bar code of FIG. 8 located on the part to be inspected (FIG. 9A) and located on a drawing of the part to be inspected (FIG. 9B), in another step of the method of FIG. 5 according to an embodiment of the present invention

FIG. 10 is a view of a display screen illustrating another step in the method of FIG. 5 showing any one of a plurality of steps to be taken in the inspection plan generated for a part to be inspected, according to an embodiment of the present invention;

FIG. 11 is a flowchart of various steps in a method according to another embodiment of the present invention for generating an inspection plan for a part to be inspected, for generating a bar code associated with that inspection plan, and for reading the bar code and carrying out the steps in the inspection plan;

FIG. 12 is a view of a display screen illustrating one step in the method of FIG. 11 showing the generation of an inspection plan for a part to be inspected, according to another embodiment of the present invention;

FIGS. 13A and 13B show the bar code of FIG. 12 located on a part to be inspected (FIG. 13A) and located on a drawing of a part to be inspected (FIG. 13B), in another step in the method of FIG. 11 according to another embodiment of the present invention;

FIG. 14 is a view of a display screen illustrating another step in the method of FIG. 11 showing any one of a plurality of steps to be taken in the inspection plan generated for a part to be inspected, according to an embodiment of the present invention;

FIG. 15 is a perspective view of a laser tracker according to other embodiments of the present invention; and

FIG. 16 is a perspective view of the laser tracker of FIG. 15 having computing and power supply elements attached thereto.

DETAILED DESCRIPTION

Portable articulated arm coordinate measuring machines (“AACMM”) and laser trackers are used in a variety of applications to obtain measurements of parts or objects, for example, to determine how accurately the part or object was made to the desired design specifications. Embodiments of the present invention provide advantages in allowing a user of the portable AACMM or laser tracker to access an inspection or measurement plan for a manufactured part or object with relative ease and quickness through use of a machine readable identification system, such as a bar code for example, associated with a corresponding inspection or measurement plan associated with that part or object. In the exemplary embodiment, each bar code is associated with a single part or a group of parts.

FIGS. 1A and 1B illustrate, in perspective, an AACMM 100 according to various embodiments of the present invention, an articulated arm being one type of coordinate measuring machine. As shown in FIGS. 1A and 1B, the exemplary AACMM 100 may comprise a six or seven axis articulated measurement device having a probe end that includes a measurement probe housing 102 coupled to an arm portion 104 of the AACMM 100 at one end. The arm portion 104 comprises a first arm segment 106 coupled to a second arm segment 108 by a first grouping of bearing cartridges 110 (e.g., two bearing cartridges). A second grouping of bearing cartridges 112 (e.g., two bearing cartridges) couples the second arm segment 108 to the measurement probe housing 102. A third grouping of bearing cartridges 114 (e.g., three bearing cartridges) couples the first arm segment 106 to a base 116 located at the other end of the arm portion 104 of the AACMM 100. Each grouping of bearing cartridges 110, 112, 114 provides for multiple axes of articulated movement. Also, the probe end may include a measurement probe housing 102 that comprises the shaft of the seventh axis portion of the AACMM 100 (e.g., a cartridge containing an encoder system that determines movement of the measurement device, for example a probe 118, in the seventh axis of the AACMM 100). In this embodiment, the probe end may rotate about an axis extending through the center of measurement probe housing 102. In use of the AACMM 100, the base 116 is typically affixed to a work surface.

Each bearing cartridge within each bearing cartridge grouping 110, 112, 114 typically contains an encoder system (e.g., an optical angular encoder system). The encoder system (i.e., transducer) provides an indication of the position of the respective arm segments 106, 108 and corresponding bearing cartridge groupings 110, 112, 114 that all together provide an indication of the position of the probe 118 with respect to the base 116 (and, thus, the position of the object being measured by the AACMM 100 in a certain frame of reference—for example a local or global frame of reference). The arm segments 106, 108 may be made from a suitably rigid material such as but not limited to a carbon composite material for example. A portable AACMM 100 with six or seven axes of articulated movement (i.e., degrees of freedom) provides advantages in allowing the operator to position the probe 118 in a desired location within a 360° area about the base 116 while providing an arm portion 104 that may be easily handled by the operator. However, it should be appreciated that the illustration of an arm portion 104 having two arm segments 106, 108 is for exemplary purposes, and the claimed invention should not be so limited. An AACMM 100 may have any number of arm segments coupled together by bearing cartridges (and, thus, more or less than six or seven axes of articulated movement or degrees of freedom).

The probe 118 is detachably mounted to the measurement probe housing 102, which is connected to bearing cartridge grouping 112. A handle 126 is removable with respect to the measurement probe housing 102 by way of, for example, a quick-connect interface. The handle 126 may be replaced with another device (e.g., a laser line probe, a bar code reader), thereby providing advantages in allowing the operator to use different measurement devices with the same AACMM 100. In various embodiments of the present invention, the bar code reader is used in place of the handle 126, or is mounted elsewhere on the portable AACMM, and is utilized to read or scan in machine-readable symbols (e.g. bar codes) that are indicative of measurement or inspection plans for a particular part or object to be measured by the portable AACMM. These various embodiments that utilize a bar code reader are described in detail herein after.

In exemplary embodiments, the probe housing 102 houses a removable probe 118, which is a contacting measurement device and may have different tips 118 that physically contact the object to be measured, including, but not limited to: ball, touch-sensitive, curved and extension type probes. In other embodiments, the measurement is performed, for example, by a non-contacting device such as a laser line probe (LLP). In an embodiment, the handle 126 is replaced with the LLP using the quick-connect interface. Other types of measurement devices may replace the removable handle 126 to provide additional functionality. Examples of such measurement devices include, but are not limited to, one or more illumination lights, a temperature sensor, a thermal scanner, a bar code reader or scanner, a projector, a paint sprayer, a camera, or the like, for example.

As shown in FIGS. 1A and 1B, the AACMM 100 includes the removable handle 126 that provides advantages in allowing accessories or functionality to be changed without removing the measurement probe housing 102 from the bearing cartridge grouping 112. As discussed in more detail below with respect to FIG. 2, the removable handle 126 may also include an electrical connector that allows electrical power and data to be exchanged with the handle 126 and the corresponding electronics located in the probe end.

In various embodiments, each grouping of bearing cartridges 110, 112, 114 allows the arm portion 104 of the AACMM 100 to move about multiple axes of rotation. As mentioned, each bearing cartridge grouping 110, 112, 114 includes corresponding encoder systems, such as optical angular encoders for example, that are each arranged coaxially with the corresponding axis of rotation of, e.g., the arm segments 106, 108. The optical encoder system detects rotational (swivel) or transverse (hinge) movement of, e.g., each one of the arm segments 106, 108 about the corresponding axis and transmits a signal to an electronic data processing system within the AACMM 100 as described in more detail herein below. Each individual raw encoder count is sent separately to the electronic data processing system as a signal where it is further processed into measurement data. No position calculator separate from the AACMM 100 itself (e.g., a serial box) is used, as disclosed in commonly assigned U.S. Pat. No. 5,402,582 ('582).

The base 116 may include an attachment device or mounting device 120. The mounting device 120 allows the AACMM 100 to be removably mounted to a desired location, such as an inspection table, a machining center, a wall or the floor for example. In one embodiment, the base 116 includes a handle portion 122 that provides a convenient location for the operator to hold the base 116 as the AACMM 100 is being moved. In one embodiment, the base 116 further includes a movable cover portion 124 that folds down to reveal a user interface, such as a display screen 428, as described in more detail herein after with respect to FIG. 4.

In accordance with an embodiment, the base 116 of the portable AACMM 100 contains or houses an electronic data processing system that includes two primary components: a base processing system that processes the data from the various encoder systems within the AACMM 100 as well as data representing other arm parameters to support three-dimensional (3-D) positional calculations; and a user interface processing system that includes an on-board operating system, a touch screen display, and resident application software that allows for relatively complete metrology functions to be implemented within the AACMM 100 without the need for connection to an external computer.

The electronic data processing system in the base 116 may communicate with the encoder systems, sensors, and other peripheral hardware located away from the base 116 (e.g., a LLP that can be mounted to the removable handle 126 on the AACMM 100). The electronics that support these peripheral hardware devices or features may be located in each of the bearing cartridge groupings 110, 112, 114 located within the portable AACMM 100.

FIG. 2 is a block diagram of electronics utilized in an AACMM 100 in accordance with an embodiment. The embodiment shown in FIG. 2 includes an electronic data processing system 210 including a base processor board 204 for implementing the base processing system, a user interface board 202, a base power board 206 for providing power, a Bluetooth module 232, and a base tilt board 208. The user interface board 202 includes a computer processor for executing application software to perform user interface, display, and other functions described herein.

As shown in FIG. 2, the electronic data processing system 210 is in communication with the aforementioned plurality of encoder systems via one or more arm buses 218. In the embodiment depicted in FIG. 2, each encoder system generates encoder data and includes: an encoder arm bus interface 214, an encoder digital signal processor (DSP) 216, an encoder read head interface 234, and a temperature sensor 212. Other devices, such as strain sensors, may be attached to the arm bus 218.

Also shown in FIG. 2 are probe end electronics 230 that are in communication with the arm bus 218. The probe end electronics 230 include a probe end DSP 228, a temperature sensor 212, a handle/LLP interface bus 240 that connects with the handle 126 or the LLP 242 via the quick-connect interface in an embodiment, and a probe interface 226. The quick-connect interface allows access by the handle 126 to the data bus, control lines, and power bus used by the LLP 242 and other accessories, such as a bar coder reader. In an embodiment, the probe end electronics 230 are located in the measurement probe housing 102 on the AACMM 100. In an embodiment, the handle 126 may be removed from the quick-connect interface and measurement may be performed by the laser line probe (LLP) 242 communicating with the probe end electronics 230 of the AACMM 100 via the handle/LLP interface bus 240. In an embodiment, the electronic data processing system 210 is located in the base 116 of the AACMM 100, the probe end electronics 230 are located in the measurement probe housing 102 of the AACMM 100, and the encoder systems are located in the bearing cartridge groupings 110, 112, 114. The probe interface 226 may connect with the probe end DSP 228 by any suitable communications protocol, including commercially-available products from Maxim Integrated Products, Inc. that embody the 1-Wire® communications protocol 236.

FIG. 3 is a block diagram describing detailed features of the electronic data processing system 210 of the AACMM 100 in accordance with an embodiment. In an embodiment, the electronic data processing system 210 is located in the base 116 of the AACMM 100 and includes the base processor board 204, the user interface board 202, a base power board 206, a Bluetooth module 232, and a base tilt module 208.

In an embodiment shown in FIG. 3, the base processor board 204 includes the various functional blocks illustrated therein. For example, a base processor function 302 is utilized to support the collection of measurement data from the AACMM 100 and receives raw arm data (e.g., encoder system data) via the arm bus 218 and a bus control module function 308. The memory function 304 stores programs and static arm configuration data. The base processor board 204 also includes an external hardware option port function 310 for communicating with any external hardware devices or accessories such as an LLP 242. A real time clock (RTC) and log 306, a battery pack interface (IF) 316, and a diagnostic port 318 are also included in the functionality in an embodiment of the base processor board 204 depicted in FIG. 3.

The base processor board 204 also manages all the wired and wireless data communication with external (host computer) and internal (display processor 202) devices. The base processor board 204 has the capability of communicating with an Ethernet network via an Ethernet function 320 (e.g., using a clock synchronization standard such as Institute of Electrical and Electronics Engineers (IEEE) 1588), with a wireless local area network (WLAN) via a LAN function 322, and with Bluetooth module 232 via a parallel to serial communications (PSC) function 314. The base processor board 204 also includes a connection to a universal serial bus (USB) device 312. It should be appreciated that the aforementioned bar code scanner may be connected to the AACMM 100 via one or more communications ports, such as but not limited to USB, Ethernet, Bluetooth, or Wi-Fi for example.

The base processor board 204 transmits and collects raw measurement data (e.g., encoder system counts, temperature readings) for processing into measurement data without the need for any preprocessing, such as disclosed in the serial box of the aforementioned '582 patent. The base processor 204 sends the processed data to the display processor 328 on the user interface board 202 via an RS485 interface (IF) 326. In an embodiment, the base processor 204 may also send the raw measurement data to an external computer.

Turning now to the user interface board 202 in FIG. 3, the angle and positional data received by the base processor is utilized by applications executing on the display processor 328 to provide an autonomous metrology system within the AACMM 100. Applications may be executed on the display processor 328 to support functions such as, but not limited to: measurement of features, guidance and training graphics, remote diagnostics, temperature corrections, control of various operational features, connection to various networks, and display of measured objects. Along with the display processor 328 and a liquid crystal display (LCD) 338 (e.g., a touch screen LCD) user interface, the user interface board 202 includes several interface options including a secure digital (SD) card interface 330, a memory 332, a USB Host interface 334, a diagnostic port 336, a camera port 340, an audio/video interface 342, a dial-up/cell modem 344 and a global positioning system (GPS) port 346.

The electronic data processing system 210 shown in FIG. 3 also includes a base power board 206 with an environmental recorder 362 for recording environmental data. The base power board 206 also provides power to the electronic data processing system 210 using an AC/DC converter 358 and a battery charger control 360. The base power board 206 communicates with the base processor board 204 using inter-integrated circuit (I2C) serial single ended bus 354 as well as via a DMA serial peripheral interface (DSPI) 356. The base power board 206 is connected to a tilt sensor and radio frequency identification (RFID) module 208 via an input/output (I/O) expansion function 364 implemented in the base power board 206.

Though shown as separate components, in other embodiments all or a subset of the components may be physically located in different locations and/or functions combined in different manners than that shown in FIG. 3. For example, in an embodiment, the base processor board 204 and the user interface board 202 are combined into one physical board.

Referring now to FIG. 4, an embodiment is shown of the AACMM 100 having an integrated display 428, which enables the user of the portable AACMM 100 to view various types of data or other information. The AACMM 100 includes the base 116 that includes the electronic data processing system 210 which is arranged to communicate via one or more buses 218 with the encoders associated with the bearing cartridge groupings 110, 112, 114. The base 116 includes a housing 400 with the mounting device 120 on one end and the bearing cartridge grouping 114 and arm portion 104 on an opposite end. On one side, the housing 400 includes a recess 402. The recess 402 is defined by an interior wall 404, a first side wall 406, a second side wall 408 and an end wall 410. The side walls 406, 408 are arranged on an angle relative to the mounting plane of the AACMM 100 such that the recess 402 tapers from the end adjacent the mounting device 120 to the end adjacent the arm portion 104. Adjacent the end wall 410, the housing 400 includes the handle portion 122 (FIG. 1) that is sized to facilitate the carrying of the portable AACMM 100 by the operator.

The housing 400 includes the movable cover portion 124, which includes a housing member 420 mounted to hinges 414. The movable cover portion 124 rotates about an axis between a closed position (FIG. 1A) and an open position (FIG. 4). In the exemplary embodiment, when in the open position, the movable cover portion 124 is arranged at an obtuse angle relative to the interior wall 404. It should be appreciated that the movable cover portion 124 is continuously rotatable and that the open position may be any position at which the operator can access and utilize the display screen 428. On an outside of the housing member 420 one or more indicators 432 may be mounted. The indicators 432 are visible to the operator when the movable cover portion 124 is in the closed position. The indicators 432 provide the operator with a visual indication of the communications status and/or the battery level of the AACMM 100.

A latch 415 may be used to secure a battery within the housing 400. The latch may be movably disposed in the wall 404. The latch 415 may include a tab that engages a surface of the battery to prevent inadvertent removal. The battery may be coupled to the battery pack interface 316 (FIG. 3A) and provides electrical power for the AACMM 100 when the AACMM 100 is not connected to an external power source (e.g. a wall outlet). In an exemplary embodiment, the battery includes circuitry that communicates with the electronic data processing system 210 and transmits signals that may include but are not limited to: battery charge level; battery type; model number; manufacturer; characteristics; discharge rate; predicted remaining capacity; temperature; voltage; and an almost-discharged alarm so that the AACMM can shut down in a controlled manner.

The movable cover portion 124 further includes a face member 424 disposed on one side and coupled to the housing member 420. The face member 424 includes an opening 426 sized to allow the viewing of the display screen 428. The housing member 420 and face member 424 are generally thin wall structures, formed from an injection molded plastic material for example, that define a hollow interior portion. In an embodiment, the housing member 420 or face member 424 may be formed from other materials, including but not limited to steel or aluminum sheet metal for example. On an end opposite the hinges 414, the housing member 420 includes a recessed area 434. Adjacent the recessed area 434 is a projection 436 that provides a handle that facilitates the opening of the movable cover portion 124 when in the closed position. Within the recessed area 434 is a latch member 438, which includes a spring loaded lever 440 coupled to one or more members 442. The members 442 are arranged to move substantially perpendicular to the surface of the recessed area 434 in response to movement of the lever 440. The latch member 438 is positioned such that when the movable cover portion 124 is rotated to the closed position, the lever fits within an opening 444 along the top of the recess 402. Adjacent the opening 444 are a pair of slots 446 sized to receive the member 442. When in the closed position, the slots 446 retain the members 442 and prevent the movable cover portion 124 from accidentally opening. To open the movable cover portion 124, the operator presses on the lever 440 causing the spring loaded members 442 to retract within the housing member 420. Once the members 442 are retracted, the movable cover portion 124 is free to rotate.

Arranged within the movable cover portion 124 is the display screen 428, which is mounted to the face member 424. The display screen 428 provides a user interface that allows the operator to interact and operate the AACMM 100 without utilizing or connecting an external host computer. However, if desired, the portable AACMM 100 may connect with an external computer and the display on that external computer may be used to view date and other information associated with the AACMM 100. The display 448 may display information relative to the operations being conducted with the AACMM 100, such as but not limited to the displaying of data derived from the positional encoders. In one embodiment, the display screen 428 is an LCD screen that can detect presence and location of a touch, such as by the operator's finger or a stylus for example, within the display area. The display screen 428 may comprise a touch sensitive screen having elements for detecting the touch that include but are not limited to: resistive elements; surface acoustic wave elements; capacitive elements; surface capacitance elements; projected capacitance elements; infrared photodetector elements; strain gauge elements; optical imaging elements; dispersive signal elements; or acoustic pulse recognition elements. The display 428 is arranged in bidirectional communication with the user interface board 202 and the base processor board 204 such that actuation of the display 428 by the operator may result in one or more signals being transmitted to or from the display 428.

In an embodiment, the housing member 420 may include one or more computer interfaces located along either or both of the sides of the display screen 428. The interfaces allow the operator to connect the user interface board 202 to an external device, such as but not limited to: a computer; a computer network; a laptop; a barcode reader or scanner; a digital camera; a digital video camera; a keyboard; a mouse; a printer; a personal digital assistant (PDA); or a cellular phone for example. One of the interfaces may comprise a USB host interface and the other interface may comprise a secure digital card interface. As discussed above, the user interface board 202 includes a processor 328 that is arranged in bidirectional communication to accept and transmit signals from the display screen 428 and the electronic data processing system 210.

It should be appreciated that when the movable cover portion 124 is in the open position it is desirable to prevent or minimize impacts on the display screen 428. In the exemplary embodiment, the arm portion 104 is configured such that the position and length of the arm segments 106, 108 do not allow the probe housing 102, a probe tip 118 or the handle 126 to impact the display screen 428 as the probe end of the arm portion 104 is moved about the area adjacent the movable cover portion 124. As such, the travel of the arm portion 104 results in a path that defines an outer periphery of travel for the probe end that results in a gap distance between the closest part of the probe end (e.g., the probe tip 118) and the display screen 428 when the display screen 428 is in an open position. In an embodiment, the movable cover portion 124 is fully open in the open position of the display screen 428. The path is arranged such that as the probe end moves downward (e.g., towards the mounting ring end), the probe end is carried away from the base 116 such that the probe end does not impact or contact the display screen 428. It should be appreciated that providing the gap distance with a distance greater than zero provides an advantage in reducing or eliminating the potential for contact between the display screen 428 and the probe tip 118.

The afore described portable AACMM 100 may comprise any type of multi-axis coordinate measurement machine, including the FARO® EDGE seven-axis articulated arm CMM or the FARO GAGE® six-axis articulated arm CMM—both available from FARO Technologies, Inc. of Lake Mary, Fla. However, any other type or make and model of coordinate measurement machine may be utilized in accordance with various embodiments of the present invention. For example, embodiments of the present invention may comprise a computer-aided manufacturing (CAM) based system that uses structured light. Other machines or devices that may embody the present invention include bridge CMMs, total stations, micrometers, or other types of dimensional metrology equipment.

Referring now to FIG. 5, there illustrated is a flowchart 500 that shows steps in a method of an embodiment of the present invention. The method may be utilized to generate a measurement or inspection plan for a part or object to be measured by the CMM 100, to assign or associate a bar code with that inspection plan, and to carry out the inspection plan by calling up that plan through use of the bar code assigned to that plan. FIGS. 6-10 illustrate the various steps in the method shown in the flowchart 500 of FIG. 5.

Referring also to FIG. 6, an inspection plan is generated in a step 510 for the part or object to be measured. The part or object to be measured may be any type of part or object that is manufactured in any way (e.g., by machining). It is commonly desired to measure or inspect the manufactured part to determine if certain various physical features of the part satisfactorily meet the desired design dimensions. The FARO GAGE® portable articulated arm CMM is typically used for this express purpose. FIG. 6 illustrates a view 600 on the display screen 428 of the AACMM 100 or on a display screen of an external computer that visually shows a step in the process of generating the inspection plan. The display screen 428 may comprise that described herein above with respect to the portable articulated arm CMM 100 in FIG. 4 in which the display screen 428 is integrated into the CMM 100. In another embodiment, the display screen may comprise the visual display screen in an external computer (e.g., a laptop) connected with the CMM 100 of FIGS. 1-3 described herein above or with some other CMM or other device utilized.

In the example shown in FIG. 6, the CMM 100 may comprise the afore mentioned FARO GAGE® portable articulated arm CMM, which may execute inspection software such as the CAM2® software for example, also available from FARO Technologies, Inc. The CMM executes the inspection software in carrying out the basic functionality of that CMM, including inspection, measurement, and analyzing and comparing measurement data and storing the results and providing the results to the user, for example, visually in several views displayed on a display screen. The inspection software guides the operator or user of the CMM in creating an inspection plan for a particular part or object to be measured or inspected. For example, the part to be measured or inspected is of certain dimensions and may have various physical features formed therein, such as holes, slots, groves, etc. Typically, in creating the inspection plan the user or operator of the portable CMM first sets up the CMM so that it becomes operational. The user then calibrates the probe tip as directed by the software. The user can then check the accuracy of the calibration by measuring the dimensions of one or more calibrated gage blocks.

Once the CMM is calibrated, the user may then determine the accuracy of the various manufactured physical features of the part to be measured or inspected. These features may be called out on the drawing print of the part itself, or may be called out is some other way (e.g., an accompanying part manual). For example, the view 600 of FIG. 6 shows the arrow 602 pointing to one of several physical features (e.g., a length between two features of the part) that the user can select when generating the inspection plan. Other common physical features include diameters of holes, distances and/or angles between features, etc.). As each feature is selected by the user, it is saved in memory as part of the particular inspection plan being generated. As the user systematically proceeds through and selects all the various physical features to be inspected on the part, the features are saved as part of that particular inspection plan.

Next, referring also to FIG. 7, there illustrated is another view 700 shown on the display screen in which now the inspection software or other software associated with a CMM instructs the user in a step 520 to associate a bar code with the inspection plan that was just created in the step 510. The bar code can be generated by the inspection software or can already exist and be stored in memory. In the latter case, the bar code may be generated during the design phase of the part, for example, along with the design drawings for that part. As such, the generated bar code can be included on the drawings. The bar code may include the instructions for the inspection plan, or the bar code may act as a pointer to a data file (e.g., stored in memory) that contains the instructions for the inspection plan. The bar code may be generated by other software, such as CAD software, or the bar code may be added on to the drawings by third party software. For example, the bar code may be generated by a machinist along with the CNC program to operate a milling machine. The bar code may further be printed by the software onto media (e.g. an adhesive label) or the part itself.

The bar code can be selected and added by the user to the inspection plan. The inspection software facilitates this step through use of the arrow 702 shown on the view 700 in FIG. 7. The bar code generated or added may comprise any type of machine readable symbol now known or hereinafter developed, including, for example, the well-known two-dimensional (2-D) Aztec code. (ISO/IEC 24778.2008 standard) Other types of 2-D or 3-D machine readable symbols may be utilized. The 2-D Aztec code is capable of supporting a maximum of 1914 bytes of data within the code. Given this relatively large amount of data within the Aztec code, it is possible that not only can the Aztec code store information about an inspection plan for the part, but the Aztec code may also be able to store or contain within itself additional information, such as information about the part or object itself (e.g., various physical characteristics and/or identifying features—model number—of the part or object). As such, the CMM can identify and obtain information about the part solely from the information contained in the bar code.

Referring also to FIG. 8, there illustrated is another view 800 shown on the display screen in which the generated or selected bar code 802 is shown in the view 800 on the left side thereon. As such, in a step 530 of the method of FIG. 5 the bar code 802 is now saved together with its associated inspection plan previously generated in the step 510; for example the bar code and its inspection plan may be stored together in a file in memory within the CMM and/or in an external computer connected with the CMM.

Referring also to FIG. 9, including FIGS. 9A and 9B, there illustrated is the bar code previously generated in the step 510 of the method of FIG. 5 and showing the bar code 802 of FIG. 8 located on a part 900 to be inspected (FIG. 9A) and located on a drawing 902 (e.g., a CAD drawing) of the part 900 to be inspected (FIG. 9B), according to a step 540 in the method 500 of FIG. 5. In FIG. 9A, after the bar code 802 has been generated, it may be applied to the part 900 in various ways; for example, in the form of a sticker that is attached to the part 900 to be inspected (FIG. 9A), or printed directly onto the drawing 902 of the part (FIG. 9B). As discussed herein above, that bar code 802 may contain information about a inspection plan for the part 900. Also, as mentioned herein above, the bar code 802 may contain additional information, for example information about the part itself 900, such as various physical characteristics or identifying features of the part 900.

Nevertheless, once the bar code 802 is associated with a part or with a drawing of a part, a bar code reader or scanner may be utilized to read the bar code 802 in a step 550 of the method of FIG. 5. For example, as mentioned herein above, the bar coder reader may be a part of the portable AACMM 100 of FIGS. 1-4; specifically, the bar code reader may be attached to the CMM 100 in place of the handle 126. However, the bar code reader or scanner is not to be limited as such. Instead, the bar coder reader may be any type of bar coder reader; for example, a hand-held stand-alone reader not associated with any type of coordinate measurement machine. Another example is reading the bar code using a common cell phone or “smartphone” having a camera feature. Still another example is the use of a camera in a laser line probe to read the bar code.

As such, once these readers read or scan the bar code, the reader may then communicate the as-read code to a coordinate measurement machine or other type of measuring device to enable that machine or device to then carry out the inspection plan. The communication of the as-read bar code can take place by various ways, including wired or wireless configurations.

Referring to FIG. 10, once the user scans in the bar code 802 from the part itself 900 or from the drawing 902 of the part 900, the machine readable symbol is translated to ascertain the information embedded therein. From this information the associated inspection plan is determined, such as from a database or lookup table for example. The inspection plan opens up in an embodiment; for example, as seen in the view 900 of FIG. 9. The user is then prompted by the inspection software or other software in a step 560 of the method of FIG. 5 to carry out the various steps in the inspection plan.

In an alternative embodiment of the present invention, once the inspection plan has been completed (for example as per the steps outlined in FIGS. 6-10 above) and the actual or “as-built” dimensions of the part or object being inspected have been obtained by, for example, the CMM 100, those actual dimensions may themselves be output as part of a 2-D bar code which may comprise a “sticker” that is attached to the part that was just inspected. This way, those actual dimensions can be utilized later on in various ways; for example, to “custom match” another mating part to the inspected part. More specifically, if the inspected part is on the “high side” in terms of actual dimensions, then another mating part may also be selected having dimensions that are also on the “high side,” thereby insuring a relatively better fit together.

In still another embodiment of the present invention, a person (e.g., a mechanic) may take a picture of the bar code on the measured part with, e.g., his cell phone, and an application on the phone displays the actual measured dimensions. This may act as a final confirmation to the mechanic before he installs the part.

Referring now to FIG. 11, there illustrated is a flowchart 1100 that shows steps in a method of another embodiment of the present invention. The method may be utilized to generate a measurement or inspection plan for a part or object to be measured by the CMM 100, to assign or associate a bar code with that inspection plan, and to carry out the inspection plan by calling up that plan through use of the bar code assigned to that plan. FIGS. 12-14 illustrate the various steps in the method shown in the flowchart 1100 of FIG. 11.

Referring also to FIG. 12, there illustrated is a view 1200 on the display screen 428 of the AACMM 100 or a display screen of an external computer. The view 1200 visually shows a step in the process of generating the inspection plan and associating a bar code with it. More specifically, the view 1200 shows a step where a user or operator of software either generates a bar code for the inspection plan or adds a bar code to the inspection plan. The software may correspond to CAD-based measurement software, CAD-based construction software, or some other type of software which contains design features of a part or object to be manufactured. The software may run on a CMM or some other type of coordinate measurement machine, or an external computer that can connect with a CMM or coordinate measurement machine. As part of this view 1200, the user may select the various features of the part or object to be inspected or measured. The selected features may then be compiled into a measurement or inspection plan that is represented by the generated or selected bar code. The inspection plan itself may be integrated with the part design file (e.g., the CAD file for the particular part).

Referring also to FIGS. 13A and 13B, there illustrated is the bar code previously generated or selected in FIG. 12 and showing a bar code 1304 located on a part 1300 to be inspected (FIG. 13A) and located on a drawing 1302 (e.g., a CAD drawing) of a part 1300 to be inspected (FIG. 13B), according to a step 1120 in the method of FIG. 11. In FIG. 13A, after the bar code 1104 has been generated, it may be applied to the part 1100, for example, in the form of a sticker attached to the part 1100 to be inspected (FIG. 11A), printed directly onto the drawing 1102 of the part (FIG. 11B) or otherwise affixed to the part (e.g. laser etching or printing the bar code onto the part). As discussed herein above, the bar code 1104 may contain information about a inspection plan for the part 1100 that is part of the CAD file or some other design file for the particular part. Also, as mentioned herein above, the bar code 1104 may contain additional information, for example information about the part itself 1100, such as various physical characteristics or identifying features of the part 1100.

Nevertheless, once the bar code 1104 is associated with a part 1100 or with a drawing 1102 of a part 1100, a bar code reader or scanner may be utilized to read the bar code 1104 in a step 1130 of the method 1100 of FIG. 11. For example, as mentioned herein above, the bar coder reader may be a part of the portable AACMM 100 of FIGS. 1-4; specifically, the bar code reader may be attached to the CMM 100 in place of the handle 126 directly or connected to communicate via the wireless communications ports of the AACMM 100. However, the bar code reader or scanner is not to be limited as such. Instead, the bar coder reader may be any type of bar coder reader; for example, a hand-held stand-alone reader not associated with any type of coordinate measurement machine. As such, once this reader reads or scans the bar code, the reader then would need to communicate the as-read code to a coordinate measurement machine or other type of measuring device to enable that machine or device to then carry out the inspection plan.

Referring also to FIG. 14, once the user scans in the bar code 1104 from the part itself 1100 or from the drawing 1102 the machine readable symbol is translated to determine the embedded information. From this information, the associated inspection plan may be identified. Once identified, the inspection plan opens up in inspection software; for example, as seen in the view 1200 of FIG. 12. The user is then prompted by the software in a step 1140 to carry out the various steps in the inspection plan to ultimately determine if the manufactured part is within the design tolerances for that part.

As mentioned herein above, embodiments of the present invention are not limited for use with portable articulated arm coordinate measurement machines. Instead, embodiments of the present invention may be utilized with other types of measurement machines or devices; for example a laser tracker, which is a common type of part or object measurement machine.

Referring now to FIGS. 15 and 16, there illustrated is an embodiment of a laser tracker 1530 that may be utilized in embodiments of the present invention. The laser tracker 1530 includes a gimbaled beam-steering mechanism 1532 that comprises a zenith carriage 1534 mounted on an azimuth base 1536 and rotated about an azimuth axis 1538. A payload 1540 is mounted on the zenith carriage 1534 and is rotated about a zenith axis 1542. The zenith mechanical rotation axis 1542 and the azimuth mechanical rotation axis 1538 intersect orthogonally, internally to the tracker 1530, at a gimbal point 1544, which is typically the origin for distance measurements. A laser beam 1546 virtually passes through the gimbal point 1544 and is pointed orthogonal to the zenith axis 1542. In other words, the laser beam 1546 is in the plane normal to the zenith axis 1542. The laser beam 1546 is pointed in the desired direction by motors (not shown) located within the tracker 1530 that rotate the payload 1540 about the zenith axis 1542 and the azimuth axis 1538. Zenith and azimuth angular encoders (not shown), located internal to the tracker 1530, are attached to the zenith mechanical axis 1542 and to the azimuth mechanical axis 1538, and indicate, to a relatively high degree of accuracy, the angles of rotation. The laser beam 1546 travels to an external target, such as a retroreflector 1548; for example, a spherically mounted retroreflector (SMR). Other types of targets are possible for use with laser trackers; for example, there exist many types of six degree of freedom (6-DOF) probes). By measuring the radial distance between the gimbal point 1544 and the retroreflector 1548 and the rotation angles about the zenith and azimuth axes 1542, 1538, the position of the retroreflector 1548 is found within the spherical coordinate system of the tracker 1530.

The laser beam 1546 may comprise one or more laser wavelengths. For the sake of clarity and simplicity, a steering mechanism of the type shown in FIG. 15 is assumed in the following discussion. However, other types of steering mechanisms are possible. For example, it may be possible to reflect a laser beam off a mirror rotated about the azimuth and zenith axes 1538, 1542. An example of the use of a mirror in this way is disclosed in U.S. Pat. No. 4,714,339 to Lau et al. The techniques described here are applicable, regardless of the type of steering mechanism utilized.

In the laser tracker 1530, one or more cameras 1550 and light sources 1552 are located on the payload 1540. The light sources 1552 illuminate the one or more retroreflector targets 1548. The light sources 1552 may be LEDs electrically driven to repetitively emit pulsed light. Each camera 1550 may comprise a photosensitive array and a lens placed in front of the photosensitive array. The photosensitive array may be a CMOS or CCD array. The lens may have a relatively wide field of view, for example, thirty or forty degrees. The purpose of the lens is to form an image on the photosensitive array of objects within the field of view of the lens. Each light source 1552 is placed near a camera 1550 so that light from the light source 1552 is reflected off each retroreflector target 1548 onto the camera 1550. In this way, retroreflector images are readily distinguished from the background on the photosensitive array as their image spots are brighter than background objects and are pulsed. In an embodiment, there are two cameras 1550 and two light sources 1552 placed symmetrically about the line of the laser beam 1546. By using two cameras 1550 in this way, the principle of triangulation can be used to find the three-dimensional coordinates of any SMR 1548 within the field of view of the camera 1550. In addition, the three-dimensional coordinates of the SMR 1548 can be monitored as the SMR 1548 is moved from point to point. A use of two cameras for this purpose is described in U.S. Published Patent Application No. 2010/0128259 to Bridges.

Other arrangements of one or more cameras 1550 and light sources 1552 are possible. For example, a light source 1552 and a camera 1550 can be coaxial or nearly coaxial with the laser beams 1546 emitted by the tracker 1530. In this case, it may be necessary to use optical filtering or similar methods to avoid saturating the photosensitive array of the camera 1550 with the laser beam 1546 from the tracker 1530.

Another possible arrangement is to use a single camera 1550 located on the payload or base 1540 of the tracker 1530. A single camera 1550, if located off the optical axis of the laser tracker 1530, provides information about the two angles that define the direction to the retroreflector 1548 but not the distance to the retroreflector 1548. In many cases, this information may be sufficient. If the 3-D coordinates of the retroreflector 1548 are needed when using a single camera 1550, one possibility is to rotate the tracker 1530 in the azimuth direction by 180 degrees and then to flip the zenith axis 1542 to point back at the retroreflector 1548. In this way, the target 1548 can be viewed from two different directions and the 3-D position of the retroreflector 1548 can be found using triangulation.

Another possibility is to switch between measuring and imaging of the target 1548. An example of such a method is described in international application WO 03/062744 to Bridges et al. Other camera arrangements are possible and can be used with the methods described herein.

As shown in FIG. 16, an auxiliary unit 1560 is usually a part of the laser tracker 1530. The purpose of the auxiliary unit 1560 is to supply electrical power to the laser tracker body and in some cases to also supply computing and clocking capability to the system. It is possible to eliminate the auxiliary unit 1560 altogether by moving the functionality of the auxiliary unit 1560 into the tracker body. In most cases, the auxiliary unit 1560 is attached to a general purpose computer 1562. Application software loaded onto the general purpose computer 1562 may provide application capabilities such as reverse engineering. It is also possible to eliminate the general purpose computer 1562 by building its computing capability directly into the laser tracker 1530. In this case, a user interface, preferably providing keyboard and mouse functionality is built into the laser tracker 1530. The connection between the auxiliary unit 1560 and the computer 1562 may be wireless or through a cable of electrical wires. The computer 1562 may be connected to a network, and the auxiliary unit 1560 may also be connected to a network. Plural instruments, for example, multiple measurement instruments or actuators, may be connected together, either through the computer 1562 or the auxiliary unit 1560.

Use of embodiments of the laser tracker 1530 of FIGS. 15 and 16 in embodiments of the present invention typically involve use of the one or more cameras 1550 on the laser tracker 1530 to read or scan a bar code that may be placed on a target (e.g., the SMR 1548) or on drawings of a part to be inspected. The software used to read, translate and interpret the machine readable symbol can be stored in the tracker body itself, in the auxiliary unit 1560, or in the computer 1562. That is, similar to the embodiments discussed herein above with respect to the portable AACMMs, the laser tracker 1530 may contain software that allows a user to create an inspection plan for a part or object to be measured or inspected by the laser tracker. The software may then allow the user to generate or select a bar code that identifies the associated inspection plan. The bar code may then be placed on the target 1548 or on a drawing that illustrates the part, and the laser tracker 1530 may then utilize one or more of its cameras 1550 to read the bar code and then carry out the corresponding inspection plan.

While the invention has been described with reference to example embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 

What is claimed is:
 1. A method for inspecting a part according to an inspection plan, the method using a portable articulated arm coordinate measuring machine (AACMM) having a base; a manually positionable arm portion having opposed first and second ends, the second end of the arm portion being coupled to the base, the arm portion including a plurality of connected arm segments, each arm segment including at least one position transducer for producing a position signal; a measurement device coupled to the first end of the arm portion; and an electronic circuit which receives the position signal from the at least one position transducer and provides data corresponding to a position of the measurement device; the method comprising the steps of: generating an inspection plan for a part to be inspected to determine at least one characteristic of the part; generating a machine readable information symbol that includes information that identifies the generated inspection plan; associating the generated machine readable information symbol with the part; reading the machine readable information symbol from the part with a reader device configured to translate the machine readable information symbol to determine the information contained therein, the reader device being coupled to communicate with the AACMM; and measuring the at least one part characteristic according to the generated inspection plan identified by the machine readable symbol.
 2. The method of claim 1 wherein the machine readable symbol is bar code.
 3. The method of claim 2 wherein the bar code is compliant with the ISO/IEC 24778.2008 standard.
 4. The method of claim 1 wherein the step of associating the machine readable information symbol with the part includes the step of further comprises affixing the bar code to the part.
 5. The method of claim 1 wherein the step of associating the machine readable information symbol with the part includes the step of further comprises affixing the bar code to a drawing of the part.
 6. The method of claim 1 further comprising the step of displaying the generated inspection plan in response to the reader device reading the machine readable information symbol.
 7. The method of claim 6 wherein the generated inspection plan is displayed on a display coupled to the AACMM.
 8. A method for inspecting a part according to an inspection plan, the method using a laser tracker having a light source that emits a light beam towards a target located within an environment, and a reader device that captures the light beam reflected back to the laser scanner from the target located within the environment; the method comprising the steps of: generating an inspection plan for a part to be inspected to determine at least one characteristic of the part; generating a machine readable information symbol that identifies the generated inspection plan; associating the generated machine readable information symbol with the part; reading the machine readable information symbol with the reader device associated with the laser tracker; and inspecting the part according to the generated inspection plan identified by machine readable information symbol read by the reader device.
 9. The method of claim 8 wherein the machine readable information symbol is a bar code.
 10. The method of claim 9 wherein the bar code is compliant with the ISO/IEC 24778.2008 standard.
 11. The method of claim 8 wherein the step of associating the generated machine readable information symbol with the part includes affixing the generated machine readable information symbol to the part.
 12. The method of claim 8 wherein the step of associating the generated machine readable information symbol with the part includes affixing the generated machine readable information symbol to a drawing of the part.
 13. The method of claim 8 further comprising the step of displaying the generated inspection plan in response to the data capture component reading the machine readable information symbol.
 14. The method of claim 13 wherein the generated inspection plan is displayed on a display coupled to the laser tracker. 